I get horrible PMS... I get very irritated at things that normally wouldn't bother me. Then come the cramps... if I'm not constantly knocking back the Advil, I'm curled up in a little ball unable to move.
There was a study done once, that showed that women living together in groups (e.g. prisons, dorms) all got their periods at the same time. My husband has already decided that when we have a teenage daughter or two, he will be scheduling week-long business trips once a month...
If this is true, it's just as well my sorority didn't have a house... I'd hate to have to sit through THAT chapter meeting